The overall objective of this project is to identify genes involved in the evolution of complex trait variation in natural populations. The proposed reseach will investigate genetic variation growth form in natural hybrid populations of Dubautia in the Hawaiian silversword alliance. The tremendous amount of variation exhibited by closely related taxa and the availability of natural hybrid populations gives the silversword alliance unique advantages for the study of adaptive variation in growth form. Proposed experimental approaches include identifying genetic markers associated with trait variation, evaluating genes known to cause dwarfing in Arabidopsis and cereal crops for association with phenotypic variation, and evaluating levels and patterns of gene expression in a larger set of candidate genes. The proposed research will test the extent to which discoveries in model genetic organisms can be extrapolated to species with longer lifespans and more complex life histories.